An inflatable vehicle occupant protection device, such as an air bag, is inflated by inflation gas provided by an inflator. The inflator contains a gas generating material. The inflator further includes an igniter. The igniter is actuated to ignite the gas generating material when the vehicle experiences a collision for which inflation of the air bag is desired. As the gas generating material burns, it generates a volume of inflation gas. The inflation gas is directed into the air bag to inflate the air bag. When the air bag is inflated, it expands into the vehicle occupant compartment and helps to protect the vehicle occupant.
It is known to use, in a gas generating material, a nitrous oxide (N.sub.2 O) oxidizer and a volatile liquid fuel such as a hydrocarbon or an alcohol. At the storage and operating pressures conventionally used for such gas generating material, nitrous oxide is in a gaseous state and the fuel is in a liquid state. An inflator using such gas generating material requires a containment system for the gas generating material which is leak-proof for the life of the inflator. In addition, since the fuel is a liquid, the surface or reaction area presented by the fuel for reaction with the nitrous oxide gas can vary substantially from one moment to the next and/or be irregular, resulting in variable and unpredictable burn rates.